Maybe I misunderstand...but "space headphone only" will, if selected, put the "space" parameter in the phones only...so he is certainly getting "space" in his phones...not missing anything?
This is for the headphone jack on the Kemper, no the Focusrite. I contacted the Kemper support and they said the headphone jack on the focusrite are inferior to the Kemper, thats why i notice this unconfortably difference in the tone.
Many have said this here in the forum and elsewhere, so it's nothing new.
The only real issue Leo had IMHO was the popping one, which slaving the interface to the Kemper's clock fixed (you're welcome, Leo).
Time for a thread-title change, methinks.
I got the Scarlett a few months ago and never noticed how bad the headphone jacks are. The popping's definitely stopped (thanks buddy <3)
Thanks once again lovely people, case closed !
Think I found the problem:
When I listen to the Kpa via headphones on my Scarlett the sound kinda sucks, but if I listen via the headphone jack on the kemper, the sound is full and complete.
Didnt expect the headphones jack on the scarlett to be so idk, bad !
Thanks everyone for your tips, all of them realy helped me out
Cheers 
Here are some clips:
- First one is stock Top Jimi's, and the second one is with the TH Diezel Hagan cabinets.
- Fixed the clock problem and made the focusrite the slave for the Kpa.
I bought a few Top Jimi profiles and tried to record some stuff, but it sounds absolutly nothing like his demo's. It sounds gnarly, muffled and bassy.
Actually most profiles I use sound wierd
Tried recording via SPDIF but the sound pops too much (clock on kemper set to 48k and on Reaper also). Then tried to record via Main Outputs directly to the Focusrite 18i8 and still sounds the same.
Im using a Gibson Les Paul Standard 2018, straight into the KPA front input, Main Outputs to Scarlett Inputs, directly to my Yamaha HS5's
Here are some pictures from my settings;
